¹ Blackwater changed its name to Xe in February 2009, but is still commonly referred to as Blackwater – a practice I shall adopt here. For accounts of the privatization of war, and new forms of warfare in general, see, e.g., Duyvesteyn, I. and Angstrom, J., eds, Rethinking the Nature of War (London: Frank Cass, 2005)Google Scholar; Kaldor, M., New and Old Wars, 2nd edn (Cambridge: Polity, 2006)Google Scholar; Munkler, H., The New Wars (Oxford: Polity, 2005)Google Scholar. For typologies of PMCs and reviews of their activities in recent conflicts, see, e.g., Scahill, J., Blackwater: The Rise of the World’s Most Powerful Mercenary Army (London: Profile Books, 2007)Google Scholar; Avant, D. D., The Market for Force: The Consequences of Privatizing Security (Cambridge: Cambridge University Press, 2005)CrossRefGoogle Scholar; Kinsey, C., Corporate Soldiers and International Security: The Rise of Private Military Companies (London: Routledge, 2006)Google Scholar; Singer, P. W., Corporate Warriors: The Rise of the Privatized Military Industry (Ithaca, N.Y.: Cornell University Press, 2003)Google Scholar, esp. chap. 1. The estimate of the number of private contractors relative to the number of British soldiers in Iraq is quoted from Scahill, Blackwater, p. 161; Avant, The Market for Force, p. 2, cites the same figure for 2004. Note that in this article, I deal with private military corporations, rather than private security companies, to the extent that the former, unlike the latter, are deployed in war theatres.

² Whether or not using private military corporations and/or private soldiers is the best way (functionally) to conduct a war is a separate question that I shall not address here. Functional concerns include, for example, the practice by private actors of defaulting on their contractual duties when the military situation of their employers is deteriorating, or the fact that contractual relationships (which set out fixed rights and duties) are not suited to the conduct of war (which requires flexible and quick decisions under changeable circumstances.) See, e.g., Avant, The Market for Force, and Schmitt, M., ‘Humanitarian Law and Direct Participation in Hostilities by Private Contractors or Civilian Employees’, Chicago Journal of International Law, 5 (2005), 511–546Google Scholar.

³ See art. 1 of the 1989 International Convention against the Recruitment, Use, Financing and Training of Mercenaries, and art. 47 of the 1977 Geneva Protocol I Additional to the Geneva Conventions of 1949. For discussions of those definitional difficulties, see, e.g., Percy, S., Mercenaries: The History of a Norm in International Relations (Oxford: Oxford University Press, 2007)CrossRefGoogle Scholar, chap. 2; Coady, C. A. J., Morality and Political Violence (Cambridge: Cambridge University Press, 2008)Google Scholar, chap. 10; Burmester, H. C., ‘The Recruitment and Use of Mercenaries in Armed Conflicts’, American Journal of International Law, 12 (1978), 37–56CrossRefGoogle Scholar.

⁴ For the interest theory of rights, see, e.g., Raz, J., The Morality of Freedom (Oxford: Clarendon Press, 1986)Google Scholar, and Kramer, M., ‘Rights without Trimmings’, in M. Kramer, H. Steiner and N. Simmonds, A Debate over Rights (Oxford: Oxford University Press, 1998), pp. 7–112Google Scholar. For the distinction between claims, powers and liberties, see Hohfeld, W. N., Fundamental Conceptions as Applied in Judicial Reasoning (New Haven, Conn.: Yale University Press, 1919)Google Scholar.

⁵ See, e.g., evidence of abuse perpetrated by so-called private contractors (as well as US soldiers) at the Abu Ghraib prison in Iraq in 2003. The report on the official investigation into such abuses can be found at http://fl1.findlaw.com/news.findlaw.com/hdocs/docs/dod/fay82504rpt.pdf (accessed on 23 February 2009). See also reports of killings of civilian bystanders in Iraq by private contractors in an October 2007 memorandum prepared for the Oversight Committee of the US Congress House of Representatives (http://oversight.house.gov/documents/20071001121609.pdf – accessed on 23/02/09).

⁶ Walzer’s, Michael Just and Unjust Wars, 4th edn (New York: Basic Books, 2006)Google Scholar remains the locus classicus in the ever-growing literature on the Just War. For the purpose of this article, I need not provide a full specification of the conditions for a Just War.

⁷ For an argument along those lines, see Suarez, F., ‘De Bello’, in his De Triplici Virtute Theologica, Fide, Spe, et Charitate, VI, 12, reproduced in J. B. Scott, ed., Selections from Three Works of Francisco Suarez, S. J. (Oxford: Clarendon Press, 1944)Google Scholar.

⁸ Generally, it is not a necessary condition for a change in A and B’s moral/legal relationship validly to take place that both A and B have the relevant power (if A gives G to B, A thereby changes their moral relationship in respect of G, without B having to exercise the same power). Here, however, I focus on exchanges.

⁹ In my ‘Mandatory Rescue Killing’, Journal of Political Philosophy, 15 (2007), 363–84, at pp. 366–8, I argue that giving a gun to someone who needs it in self-defence, and killing (for free) that person’s attacker, are relevantly analogous. The argument applies, mutatis mutandis, to the act of selling a gun and the act of killing against payment.

¹⁰ As a referee for this Journal pointed out, my argument for mercenarism, which appeals to the value of enabling Just War killings, raises the interesting issue of the extent to which a PMC’s contractual obligations to state A may be allowed to override a non-contracting state B’s urgent need for military manpower. Should the PMC be allowed to default on the contract it made with A at time t ₁, so as to help B whose needs at time t ₂ are more pressing? Or should it be held to its contractual obligations to A? Of course, the issue arises, not merely in the context of mercenarism, but whenever private actors are allowed to contribute to helping those in need: if a company is under contract with hospital H₁ for the delivery of medical equipment, should it be allowed to default on its contract for the sake of supplying H₂, which is facing an unexpected shortage in surgical instruments? And so on. I lack the space to deal with those complications here. Some of the concerns that they raise are ethical, whilst others are more functional (cf. fn. 2).

¹¹ See, e.g., http://www.nytimes.com/2005/09/28/national/28england.html, http://www.nytimes.com/2005/01/28/international/middleeast/28abuse.html, and http://www.nytimes.com/2008/12/06/washington/06blackwater.html?_r=1 (sources consulted on 22 February 2009). The US War Crimes Act (18 USC §2441 (1996 and 2004)) provides that any American national or member of the US Armed Forces who commits a war crime is liable to prosecution: it would thus apply to American, but not foreign, PMC employees. In December 2008, US federal prosecutors charged five Blackwater guards with a shooting that killed at least seventeen civilians in a crowded Baghdad square. For discussions of the legal status of mercenaries and employees of PMCs, see, e.g., Cameron, L., ‘Private Military Companies: Their Status under International Humanitarian Law and Its Impact on Their Regulation’, International Review of the Red Cross, 88 (2006), 573–598CrossRefGoogle Scholar; Fallah, K., ‘Corporate Actors: The Legal Status of Mercenaries in Armed Conflict’, International Review of the Red Cross, 88 (2006), 599–611CrossRefGoogle Scholar; Gillard, E.-C., ‘Business Goes to War: Private Military/Security Companies and International Humanitarian Law’, International Review of the Red Cross, 88 (2006), 525–572CrossRefGoogle Scholar; Doswald-Beck, L., ‘Private Military Companies under International Humanitarian Law’, in Simon Chesterman and Chia Lehnardt, eds, From Mercenaries to Market: The Rise and Regulation of Private Military Companies (Oxford: Oxford University Press, 2007), pp. 115–139CrossRefGoogle Scholar.

¹² The qualification is important. One might think, for example, that a conscript should not be subject to as severe a punishment, for taking part in an unjust war, as a mercenary, precisely because he is subject to considerable duress.

¹³ That claim is compatible with the (plausible) view that there are differences between armies’ and private companies’ duties and permissions before the war starts – such that, e.g., the army is under a collective duty to go to war as ordered by its (civilian) political leaders, but a private company is not under a duty to accept a government’s contract to fight in that war. For interesting discussions of differential liabilities for uniformed soldiers and mercenaries, see Pattison, J., ‘Just War Theory and the Privatization of Military Force’, Ethics and International Affairs, 22 (2008), 143–162CrossRefGoogle Scholar, and Coady, Morality and Political Violence, pp. 226ff (though Coady is sceptical of the legitimacy of mercenarism).

¹⁴ See Scahill, Blackwater, chap. 8.

¹⁵ On that plausible view, France and Britain have the right (and the duty) to punish, respectively, non-French members of the Foreign Legion and Gurkhas. See Avant, , The Market for Force, pp. 233–5Google Scholar, for a discussion of the difficulties raised by jurisdictional confusion over extraterritorial punishment in recent conflicts.

¹⁶ For the view that ammunition factories and their workers are liable to being bombed, see, e.g., E. Anscombe, ‘War and Massacre’, and ‘Mr Truman’s Decree’, in Anscombe, E., Ethics, Religion and Politics (Minneapolis: University of Minnesota Press, 1981), pp. 53 and 67Google Scholar, respectively; Nagel, T., ‘War and Massacre’, Philosophy and Public Affairs, 1 (1972), 123–144Google Scholar, at pp. 139–40; O. O’Donovan, , The Just War Revisited (Cambridge: Cambridge University Press, 2003), pp. 38–39CrossRefGoogle Scholar and 41–2; Walzer, , Just and Unjust Wars, p. 145Google Scholar. Regarding liability to punishment, a number of leading industrialists from Flick, Krupp and IG Farben were tried in 1947–48 for complicity in Nazi Germany’s war crimes.

¹⁷ Unless the lethal threat against which they are defending themselves is itself unjust.

¹⁸ For a different argument in favour of the dependence of jus in bello on jus ad bellum, see, e.g., McMahan, J., ‘The Ethics of Killing in War’, Ethics, 114 (2004), 693–733CrossRefGoogle Scholar.

¹⁹ For the distinction, in this context, between right motives and just aims (or, as he calls them, intentions), see Pattison, ‘Just War Theory and the Privatization of Military Force’. For a comprehensive review of the motivational objection to mercenarism, see Percy, The History of a Norm in International Relations, esp. chap. 5. See also Russell, F. H., The Just War in the Middle Ages (Cambridge: Cambridge University Press, 1975)Google Scholar, chap. 6. Two classical thinkers who condemn mercenaries on motivational grounds are Machiavelli in The Prince (ed. by G. Bull) (Harmondsworth, Midx.: Penguin, 1981), chap. XII, esp. pp. 77–8, and Grotius, in The Rights of War and Peace (ed. by R. Tuck) (Indianapolis, Ind.: Liberty Fund, 2005)Google Scholar, Bk II, chap. XXV, §ix, p. 1164. For a powerful rebuttal of the motivational objection along the lines deployed in this paragraph and the next two, see Lynch, T. and Walsh, A. J., ‘The Good Mercenary?’, Journal of Political Philosophy, 8 (2000), 133–153CrossRefGoogle Scholar.

²⁰ See Scahill, Blackwater, esp. chap. 5. Suppose that uniformed soldiers in a given country decide to leave the army en masse, unless their pay is significantly raised. Would it be morally wrong of them to do so? I owe this point to Alan Hamlin.

²¹ I deploy a structurally similar argument regarding organ sales, prostitution and surrogate motherhood in my Whose Body is it Anyway? (Oxford: Oxford University Press, 2006, chaps 6–8). To illustrate here: suppose that White becomes a mercenary because he really enjoys killing. If motives are decisive to the permissibility of actions, White is acting wrongly. But that is not enough to show that White ought not to have the right to work as a mercenary – any more than the fact that someone becomes a surgeon because he gets aroused by cutting into the flesh of anaesthetized patients is enough to warrant legally preventing him from being a surgeon. One would have to show that his perverse motives lead him to provide sub-standard medical care to his patients.

²² In other words, to advert to the aforementioned distinction between two interpretations of the requirement of just intentions, the worry is that, precisely because they have the wrong motives, mercenaries are more likely to act in pursuit of wrongful aims. See Pattison, , ‘Just War Theory and the Privatization of Military Force’, p. 147 and pp. 150–2Google Scholar. To return to the example given in fn. 21, if it turned out that White’s appetite for killing made him prone to killing indiscriminately, then that would be sufficient warrant for preventing him (forcibly) from doing so. Likewise, if a surgeon’s appetite for cutting into sleeping flesh were to lead him to operate without a medical reason, that would be sufficient warrant to withdraw his licence (and put him into jail for inflicting grievous bodily harm on his patients).

²³ Coady, , Morality and Political Violence, pp. 218–19Google Scholar.

²⁴ Kant, I., ‘Perpetual Peace’, in H. Reiss, ed., Kant – Political Writings, 2nd edn (Cambridge: Cambridge University Press, 1991), p. 95Google Scholar. (See also Burchett, Wilfred and Roebuck, Derek, The Whores of War (Harmondsworth: Penguin, 1977)Google Scholar, for a similar objection in the context of the use of mercenaries in Africa in the 1970s.) According to Kant, the important difference is not between private and standing armies but, rather, between both kinds of armies on the one hand and occasional citizens’ armies on the other. He claims that standing armies should be abolished, because ‘they constantly threaten other states with war by the very fact that they are always prepared for it’ (‘Perpetual Peace’, p. 94).

²⁵ See Percy, , Mercenaries, pp. 152–3 and 160Google Scholar.

²⁶ See Scahill, , Blackwater, chaps. 5 and 13Google Scholar.

²⁷ This, in effect, is the thrust of Scahill’s critique of Blackwater’s activities. See his Blackwater, esp. chap. 13.

²⁸ For a study of the ways in which PMCs have been able to influence US foreign policy, see Avant, The Market for Force, esp. chap. 4, and Shearer, D., Private Armies and Military Intervention (Oxford: Oxford University Press, 1998), pp. 34ffGoogle Scholar. For worries about the loss of accountability attendant on states’ decisions to use PMCs, see, e.g., Singer, , Corporate Warriors, chap. 10, and Pattison, ‘Just War Theory and the Privatization of Military Force’, pp. 150ffGoogle Scholar.

²⁹ For examples of ways in which to regulate PMCs, see, e.g., Avant, , The Market for Force, chap. 4; Singer, Corporate Warriors, chap. 15; and Chesterman and Lehnardt, eds, From Mercenaries to MarketGoogle Scholar.

³⁰ See Percy, , Mercenaries, pp. 218–19, and Shearer, Private Armies and Military Intervention, chap. 4, for a strong argument along those lines. See Singer, Corporate WarriorsGoogle Scholar, chaps 1, 7 and 8 for discussions of the cases of Croatia and Sierra Leone.

³¹ See, e.g., Thomson, , Mercenaries, Pirates, and Sovereigns (Princeton, Conn.: Princeton University Press, 1994)Google Scholar, esp. chap. 3.

³² Burmester, , ‘The Recruitment and Use of Mercenaries in Armed Conflicts’, pp. 41–7Google Scholar.

³³ For a fuller argument to that effect, see my ‘Permissible Rescue Killings’, Proceedings of the Aristotelian Society, 109 (2009), 149–64.

³⁴ Burmester, , ‘The Recruitment and Use of Mercenaries in Armed Conflicts’, p. 44Google Scholar.

³⁵ All four were raised, in one way or another, at the various meetings where I have presented earlier versions of this article. I am grateful to an anonymous Journal referee for pressing me on the first one, which also arises in connection with another claim I defend elsewhere, to wit, that private individuals as such are sometimes permitted to go to war in defence of their rights. See my ‘Cosmopolitanism, Legitimate Authority and the Just War’, International Affairs, 84 (2008), 963–76.